Please note, this is a STATIC archive of website developer.mozilla.org from 03 Nov 2016, cach3.com does not collect or store any user information, there is no "phishing" involved.
The articles below will help you get your hands on the Mozilla source code, learn to navigate the code, and how to get the changes you propose checked into the tree.
If you plan to contribute to the Mozilla project, the best way to get the code is to check it out from the version control repository. Learn how to do that here.
Learn how to use MXR, Mozilla's online search and browsing tool for accessing the source code. This isn't a good way to download the code, but is a great way to search it.
Mozilla products build on at least three platforms. If you don't have access to them all, you can use the try servers to test your patches and make sure the tests pass.
Once you've made a change to the Mozilla code, the next step (after making sure it works) is to create a patch and submit it for review. This article needs to be updated fully for Mercurial.
Older versions of the Mozilla source code, as well as the current versions of NSS and NSPR, are kept in a CVS repository. Learn about that in this article.